Electromagnetic brake



June 8, 1943. H. E. HODGSON 2,321,205

ELECTROMAGNETIC BRAKE Filed Nov. 28, 1941 2 Sheets-Sheet 1 a 25 33. 18' 50v; y M 45 June 8, 1943. H. anoncssou ELECTROMAGNETIC BRAKE Filed Nov. 28,- 1941 2 Sheets-Sheet 2 Patented June 8, 1943,

ELECTROMAGNETIC BRAKE Howard E, Hodgson, Wauwatosa, Wis, assignor to Cutlenflammer, Inc., Milwaukee, Wis, a corporation of Delaware Application November 28, 1941, Serial No. 420,801

'! Claims.

This invention relates to electromagnetic brakes, and is particularly applicable disk type brakes for use in connection with eiectric motors.

The invention has among its objects to simplify and generally improve the construction and operation or brakes of the aforesaid type.

Another object is to provide a totally enclosed brake of the aforesaid type having accessible sociated rture, the brake setting spring and a friction e associated with the armature 2o cylindrical inner pole projection it and an anconstitute an assembly which is removable as a nular outer p018 p oj magnet o unit with minimum of axial displacement. l is mounted in the annular space between said,

Another object is to provide an electromagpole projections. Armature E and friction disk netic bro. having a single lever for adjusting the 9 are slidably mounted held against rotaspring and for eifecting manual vWe broke.

Various other objects and advantages of the invention v hereinafter appear.

accompanying drawings illustrate an embodiment the invention which will now be described, being understood that various modiflcations be made in the embodiment illustrated without departing from the spirit and. scope 01"" the appended claims.

In the drawings,

Figure l is a side view of a brake embodying the invention, a part of the brake being shown in section;

Fig. 2 is a front elevational view of shown in Fig. l, and a Fig. 3 is a fragmentary view of certain of the parts shown in Fig. 1.

The brake illustrated is designed for use in connection with an electric motor and as shown in Fig. l the same is provided with a. circular mounting plate I to be secured tothe motor housing 2 (partly shown) by screws 3 and a hub l to be keyed to the motor shaft 5. Mounting plate I carries an assembly including a circular field member 8, an annular magnet coil I, a circular armature 8, a circular friction disk 9 and a brake setting spring Ill. Hub 4 carries a circular friction disk II having friction linings I2 mounted upon opposite sides thereof to be clamped between mounting plate I and friction disk 9 under the action of spring II).

More specifically, mounting plate I has foot projections I3I3 formed on opposite sides thereof which are drilled to receive the securing screws 2 and the same is provided with a center release of the brake "opening for receiving an outwardly extending peripheral flange H formed on hub i. Said mounting plate has an annular gasket mounted thereon for engaging the periphery of flange I4 and the same is also provided with an annular rim projection it which surrounds the friction disk ii. Friction disk ii is provided with a center opening for receiving hub 5 and is also provided with a plurality openings for receiving pins H which are tired to the flange H 1 Friction disk iI is thus coupled rotate with hub 4 and is also free to move axially thereon.

Field member 5 is fixed within shrunk on non-magnetic ring member which is secured to the rim projection to on mounting plate 3 by screws 59. Ring member if) projects beyond the rear face of field member and a gasket is in terposed between said ring member and rim projection it on mounting plate i. The inner face of field member 5 is recessed to provide a tion upon pins 2'3 which are fixed within openings in the inner end of pole projection 20. Armature 8 is provided with a center cylindrical extension 24 having a threaded opening therein for receiving a nut 25 which is provided with an enlarged circular head 25 for engaging the front face of friction disk 9. Field member ti is provided with a center opening 21 which extends through a cylindrical projection 28 formed on the face of said field member and said opening has a threaded portion 29 for receiving an externally threaded cup nut 30. The brake setting spring III is located within opening 21 and is held under compression between cap nut 30 and the armature member 8.

As is apparanet from the foregoing, when magnet coil 1 is deenergized armature 8 is biased away from field member 6 by, spring III and the force of said spring is transmitted from armature 8 through nut 25 to friction disk 9 whereby friction disk II is clamped between friction disk 9 by a stem 3| to compensate for wear of the friction linings I2, and cup nut 30 is adjustable by a lever 32 to vary the degree of compression of spring ID for variation of the braking pressure applied to disk I I. Also as hereinafter set forth,

- lever 32 is operatively connected through stem 3| to armature 6 to provide for manual release of the brake.

' tends forwardly beyond the projection 26 on the front face of field member 6 and the front end of said stem is provided with squared portions 36 and 31 which are located on opposite sides of a collar 38.

Lever 32 comprises an elongated flat plate having a pair of spaced pins 33-33 mounted adjacent one end thereof which engage within a diametrically disposed slot 46 in the front face of cup nut 30. Lever 32. is held in assembled position upon field member 6 by a screw 4| which may be inserted into any on of a plurality of tapped openings 42 (Fig. 2) in the front end of projection 28 on field member 6, and said lever is yieldingly held against the front end of said projection by a spring 43 which is held under compression between said lever and an enlarged head on the front end of said screw. As shown in Fig. 2, lever 32 is provided with a circular opening 45 having a rectangular slot 46 on one side thereof for receiving the squared portion 36 on adjusting stem 3|.

To efi'ect manual release of the brake, lever 32 is moved forwardly from the full line position to the dotted line position shown in Fig. 1. Upon forward movement of lever 32 intoits dotted line position the inner end of said lever is fulcrumed upon the front end of projection 28 on field member 6 and collar 38 is engaged by said lever tov move stem 3| forwardly out of th position shown in Fig. 1.' Upon forward movement of stem 3| the collar 34 thereof engages shoulder 35 on extension 24 of armature member 8 to move said armature member forwardly against theacti'on of spring l and friction disk 3 is thus relieved of the pressur of said spring for release of the brake.

With lever 32 held in assembled position upon field member 6 by the screw 4| cup nut 30 is locked against rotation by engagement of pins 33 within the slot 40 in the front face of said nut and'stem 3| is locked against rotation by engagement of the squared portion 36 thereof within the rectangular slot 46 in said lever. When it is desired to effect adjustment of the brake, screw 4| is removed and lever 32 is moved longitudinally into a position wherein the squared portion 36 of stem 3| is locatedwithin the cir- .cular opening 45 in said lever. Stem 3| may then be rotated by means of a wrench applied to the squared portion 31 thereof to move' nut 33 within the extension 24 of armature 8 for axial adjustment of said armature with respect to friction plate 3. Stem 3| therefore provides for adjustment of the air gap between armature 8 and field member 6 to compensate for wear of the friction linings I2. W'hen lever 32 is disengaged from stem 3| the sam may be rotated independently of said stem to effect adjustment of cup nut 30 through the medium of the pins 33for variation of the braking pressure exerted by spring [8. As is apparent, the pin and slot connection' 3940 between cup nut 30 and lever 32.

limits inward adjustment of said nut and thereby prevents compression. of spring ,III to such a dee gree as to render the magnet pooperative to effect release of the brake. After adjustment of the brake, lever 32 is moved into locking engagement with the squared portion 36 of stem 3| and the same is then re-assembled in the required angular position upon field member 6 by means of screw 4| and spring 43.-

Upon release of the brake, friction disk 6 is yieldlngly held in engagement with the head 26 of nut 26 by a spring pressure device comprising a pin 48 and a coil spring 43 which surrounds said pin. Pin 43 is slidable within an opening in the rear end of stem 3| and the inner end of said pin extends through a center opening in friction disk 3 and has a ring 66 attached thereto for engaging the rear face of said disk. The front end of pin 48 is provided with a head II and spring 43 is held under compression against said head by pins 62 fixed to the inner end of stem 3|. a

In connection with the foregoing it should be noted that field member 6, ring member l8, ar-

mature 3, friction disk 9, spring I and the adj-usting mechanism for the brake constitutes an the non-magnetic ring ll provides for passage of substantially all of the fiux of magnet coil 1 through the armature member 8.

The front wall of field member 6 is formed to provide arectangular wiring housing 63 for receiving terminals 64 associated with the magnet coil 1. The upper wall of housing 63 is provided with a tapped conduit opening 64 and said housing is provided with a removable front cover plate 66. Cover plate 66 is secured to the housing 63 by screws 66 and has a gasket 61 interposed between the same and said housing.

What I claim as new and desire to secur by Letters Patent is:

1. A multi disk friction brake including a stationary braking element and a circular assembly detachably mounted upon said stationary braking element, said assembly being removable 'as a unit from said stationary braking element without substantial axial displacement thereof, and comprising a circular releasing magnet, a brake setting spring of coil form mounted within a center opening in said magnet, a nut threaded within the center opening in saidmagnet and rotatable to adjust said spring, and an element mounted upon the exterior of said magnet and operable to effect release of said brake, said element being also operable to adjust said nut for variation of the brake setting pressure of said spring.

2. A multi disk friction brake including a cir- .cular releasing magnet, a brake setting spring said former braking element, one of said nonrotatable brakingelements being fixed and the with said operating connection and with saidarmature member, said stem being rotatable to adjust said operating connection for variation of the position of said armature member with re:- spect to said axially movable non-rotatable element and also being movable axially to move said armature against the action of said spring for release of the brake.

4. An electromagnetic brake comprising a rotatable braking element, a pair of non-rotatable braking elements arranged on opposite sides of said former braking element, one of said nonrotatable braking elements being fixed and the other being capable of axial movement, a brake releasing magnet concentrically disposed with respect to said braking elements and detachably secured to said fixed braking element, said magnet including a stationary field member and a movable armature member, an adjustable operating connection between said armature member and said axially movable non-rotatable braking element, a brake setting sprin located within a center opening in said field member and acting through the medium of said armature member and said adjustable operating connection to effect setting of the brake, a stem associated with said operating connection and with said armature member, said stem being rotatable to adjust said operating connection for variation of the position of said armature member with respect to said axially movable non-rotatable, element and also being movable axially to move said armature against the action of said spring for release of the brake, and a lever mounted upon said magnet and operatively connected to said stem for efiecting manual release or the brake.

5. An electromagnetic brake comprising a rotatable braking element, a pair of non-rotatable braking elements arranged on opposite sides of said former braking element, one of said nonrotatable braking elements being fixed and the other being capable of axial movement, a brake releasing magnet concentrically disposed with respect to said braking elements and detachably secured to said fixed braking element, said magnet including a stationary field member and a movable armature member, an adjustable operat-' ing connection between said armature member and said axially movable non-rotatable braking element, a brake setting spring located within a center opening in said field member and acting through the medium of said armature member and said adjustable operating connection to eftect setting or the brake, a nut threaded within the center opening in said field member for adlusting said spring, a stem associated with said operating connection and with said armature member and extending through the center openin: in said nut, said stem being rotatable to adjust said operating connection for variation of the position of said armature member with respect to said axially movable non-rotatable element and ture against the action of said spring for release of the brake and a manual operating lever mounted upon the exterior of said magnet for efieoting manual release of the brake through the medium of said stem, said lever being also operable to adjust said nut for variation of the brake setting pressure of said spring.

6. An electromagnetic brake comprising a rotatable braking element, a pair of non-rotatable braking elements arranged on opposite sides of said former braking element, one of said nonrotatable braking elements being fixed and the other being capable of axial movement, a brake releasing magnet concentrically-disposed with respect to said braking elements and detachably secured to said fixed braking'element, said mag net including a stationary field member and a movable armature member, a centrally located adjusting nut associated with said armature member for engaging said movable non-rotatable braking element on one side thereof, a brake setting spring located within a center opening in said field member and acting through the medium of said armature member and said nut to effect setting of the brake, a stem associated with said nut and with said armature member, said stem being rotatable to adjust said nut for variation of the position of said armature memher with respect to said axially movable nonrotatable element and said stem being also movable axially to move said armature against the action of said spring for release of the brake, and spring means associated with said stem for holding said axially movable non-rotatable braking element in engagement with said nut upon release of the brake.

7. An electromagnetic brake comprising a r0- tatable braking element, a pair of non-rotatable. braking elements arranged on opposite sides of said former braking element, one of said nonrotatable braking elements being fixed and the other being capable of axial movement, a brake releasing magnet concentrically disposed with re spect to said braking elements and detachably secured to said fixed braking element, said magnet including a stationary field member and a movable armature member, an adjustable operating connection between said armature member and said axially movable'non-rotatable braking element, a brake setting spring located within a center opening in said field member and acting through the medium of said armature member and said adjustable operating connection to effect setting of the brake, a nut threaded within the center opening in said field member for adjusting said spring, a. stem associated with said operating connection and said armature member and extending through a center opening in said nut, said stem being rotatable to adjust said operating connection for variation of the position of said armature member with respect to said axially movable non-rotatable element and said stem being also movable axially to move said armature against the action of said spring for release of the brake, and a manual operatin lever mounted upon said magnet and operatively connected to said stem and said nut to lock the same against rotation, said lever being movable to effect axial movement of said stem for release of the brake, and said lever being also releasable from said stem to render. the same operative to eiiect adjustment of said nut independently of said stem.

HOWARD E. HODGSON. 

